Effect of a propolis extract on Streptococcus mutans counts in vivo

OBJECTIVE: To evaluate the antibacterial action of an extract of geopropolis produced by the bee Melipona compressipes fasciculata on the concentration of Streptococcus mutans colonizing the oral cavity of young patients. Forty-one young volunteers performed 21 mouth rinses divided into three rinses per day for 7 days, with no other changes in their oral hygiene and dietary habits. Saliva was collected at three time points: before the first rinse, and one hour and 7 days after the first rinse. A reduction in the concentration of S. mutans was observed in 49% of all samples collected after use of the extract, 26% showed no alterations, and an increasing in S. mutans was observed in 25%. Was performed with the Statistica for Windows 5.9 program using the Kruskal-Wallis test for analysis of variance and the Mann-Whitney U test, with the level of significance set at 5%. The propolis extract possesses in vivo antimicrobial activity against S. mutans present in the oral cavity and might be used as an alternative measure to prevent dental caries

Avaliação da influência dos tipos de tratamento superficial da porcelana glazeada na colagem de braquetes ortodônticos

OBJETIVO: o objetivo deste trabalho foi avaliar a influência do tipo de tratamento superficial da porcelana na resistência adesiva da colagem de braquetes ortodônticos e o modo de fratura após a descolagem. METODOLOGIA:foram confeccionados 80 corpos-de-prova de porcelana, divididos em quatro grupos (n = 18) de acordo com os diferentes tratamentos de superfície: (G1) ponta diamantada; (G2) ponta diamantada e silano; (G3) ácido hidrofluorídrico e (G4) ácido hidrofluorídrico e silano. Após o preparo das superfícies, braquetes Edgewise (Morelli) foram colados com resina (Transbond XT, 3M) e submetidos ao teste de cisalhamento. Os resultados foram avaliados estatisticamente pelo teste de Kruskal-Wallis. RESULTADO: o grupo G1 apresentou uma média de resistência de 3,35, o G2 3,97, o G3 2,56 e o G4 3,10. CONCLUSÃO: constatou-se que não houve diferença estatisticamente significativa na resistência adesiva do braquete entre os tipos de tratamentos estudados (p > 0,05) e os modos de fratura ocorreram, em sua grande maioria, na interface braquete/resina. Este estudo indica que todos os tipos de tratamentos apresentados são eficientes para a colagem.AIM: The aim of this study was to evaluate the influence of various porcelain surface treatments on the strength of orthodontic brackets bonded to porcelain and the fracture mode after debonding. METHODS: Eighty samples of porcelain were randomly divided into four groups according to their surface preparation, as follows: (G1) diamond bur, (G2) diamond bur with silane, (G3) hydrofluoridic acid and (G4) hydrofluoridic acid with silane. After surface treatment the Edgewise brackets (Morelli) were bonded with resin (Transbond XT, 3M) and sheared off. The Kruskal-Wallis statistical test were applied on the data. RESULTS: There were no statistically significant differences in bond strength between the groups (p > 0.05) and the fracture mode in most of the porcelain occurred in the composite/bracket interface. The G1 had an resistance average of 3.35, G2 = 3.97, G3 = 2.56 and G4 = 3.10

Effect of 2% chlorhexidine on microtensile bond strength of composite to dentin

Purpose: To evaluate the effect of 2% chlorhexidine on the microtensile bond strength of composite resin to dentin treated with three dentin bonding systems. Materials and Methods: Flat dentinal surfaces were prepared in 24 extracted human third molars. Teeth were randomly divided into 8 distinct experimental groups according to the adhesive applied (Prime & Bond NT, Single Bond and Clearfil SE Bond), the application (yes/no) of chlorhexidine, and the time point at which it was applied (before or after acid etching the dentin). Composite resin blocks were built up over treated surfaces, and teeth were then stored in water at 37°C for 24 h. Samples were thermocycled, stored under the same conditions, and then vertically sectioned, thus obtaining specimens with 1.0 ± 0.1 mm2 cross-sectional area. Specimens were stressed in tension at 0.5 mm/min crosshead speed. Bond strength results were evaluated using a one-way ANOVA (p < 0.05). The modes of failures were verified using optical microscopy. Dentin disks were obtained from 3 additional teeth treated in the same manner for observation under SEM. The most representative samples of fractured specimens were also observed under SEM. Results: No statistically significant differences of bond strength values were found between any groups. Failures occurred mainly within the bond; exclusively adhesive fractures (adhesive-dentin) were not observed. Conclusion: The 2% chlorhexidine solution, applied before or after acid etching of the dentin, did not interfere with the microtensile bond strength of composite resin to the dentin treated with Prime & Bond NT, Single Bond, or Clearfil SE Bond bonding systems